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WORM_BUZUS.HY

October 09, 2012
 Analysis by: Christopher Daniel So
 ALIASES:

VirTool:Win32/DelfInject.gen!BI (Microsoft); Trojan.ADH (Symantec)

 PLATFORM:

Windows 2000, Windows XP, Windows Server 2003

 OVERALL RISK RATING:
 DAMAGE POTENTIAL:
 DISTRIBUTION POTENTIAL:
 REPORTED INFECTION:

  • Threat Type: Worm

  • Destructiveness: No

  • Encrypted:

  • In the wild: Yes

  OVERVIEW

This worm arrives via removable drives. It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

  TECHNICAL DETAILS

File Size:

118,336 bytes

File Type:

EXE

Memory Resident:

Yes

Initial Samples Received Date:

08 Jul 2011

Arrival Details

This worm arrives via removable drives.

It arrives on a system as a file dropped by other malware or as a file downloaded unknowingly by users when visiting malicious sites.

Installation

This worm drops the following copies of itself into the affected system:

  • %Program Files%\Common Files\Reader_sl.exe

(Note: %Program Files% is the default Program Files folder, usually C:\Program Files.)

Autostart Technique

This worm adds the following registry entries to enable its automatic execution at every system startup:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
patches = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\Run
Adobe Reader Speed Launchers = "%Program Files%\Common Files\Reader_sl.exe"

Other System Modifications

This worm adds the following registry entries as part of its installation routine:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoFolderOptions = "1"

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\
Windows\CurrentVersion\policies\
Explorer
NoRun = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoFolderOptions = "1"

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Policies\
Explorer
NoRun = "1"

It modifies the following registry entries to hide files with Hidden attributes:

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
Hidden = "2"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
SuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

HKEY_CURRENT_USER\Software\Microsoft\
Windows\CurrentVersion\Explorer\
Advanced
ShowSuperHidden = "0"

(Note: The default value data of the said registry entry is 1.)

It creates the following registry entry(ies) to bypass Windows Firewall:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\
Services\SharedAccess\Parameters\
FirewallPolicy\StandardProfile\AuthorizedApplications\
List
%Program Files%\Common Files\Reader_sl.exe = "%Program Files%\Common Files\Reader_sl.exe:*:Enabled:Adobe Reader Speed Launchers"

Propagation

This worm drops the following copy(ies) of itself in all removable drives:

  • RECYCLER\S-1-5-21-1644491937-1844823847-682003330-1003\autorunme.scr

It drops an AUTORUN.INF file to automatically execute the copies it drops when a user accesses the drives of an affected system.

The said .INF file contains the following strings:

[autorun]
645FF040-5081-101B-9F08-00AA002F954E
S-1-5-21-1644491937-1844823847-682003330-1003

USEAUTOPLAY=1
open=RECYCLER\S-1-5-21-1644491937-1844823847-682003330-1003\autorunme.scr
S-1-5-21-1644491937-1844823847-682003330-1003
S-1-5-21-1644491937-1844823847-682003330-1003

action=Open folder to view files
S-1-5-21-1644491937-1844823847-682003330-1003

shell\open=Open
shell\open\command=RECYCLER\S-1-5-21-1644491937-1844823847-682003330-1003\autorunme.scr
shell\open\default=1
S-1-5-21-1644491937-1844823847-682003330-1003
S-1-5-21-1644491937-1844823847-682003330-1003

  SOLUTION

Minimum Scan Engine:

8.900

FIRST VSAPI PATTERN FILE:

8.274.11

FIRST VSAPI PATTERN DATE:

08 Jul 2011

Step 1

For Windows XP and Windows Server 2003 users, before doing any scans, please make sure you disable System Restore to allow full scanning of your computer.

Step 2

Restart in Safe Mode

[ Learn More ]

Step 3

Enable Registry Editor

[ Learn More ]
By doing this step, you also enable other applications/programs disabled by this malware/grayware/spyware.

Step 4

Restart in normal mode and scan your computer with your Trend Micro product for files detected as WORM_BUZUS.HY. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.

Step 5

Delete this registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\SharedAccess\Parameters\FirewallPolicy\StandardProfile\AuthorizedApplications\List
    • %Program Files%\Common Files\Reader_sl.exe="%Program Files%\Common Files\Reader_sl.exe:*:Enabled:Adobe Reader Speed Launchers"

Step 6

Restore this modified registry value

[ Learn More ]

Important: Editing the Windows Registry incorrectly can lead to irreversible system malfunction. Please do this step only if you know how or you can ask assistance from your system administrator. Else, check this Microsoft article first before modifying your computer's registry.

  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: Hidden="2"
      To: Hidden="1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: SuperHidden="0"
      To: SuperHidden="1"
  • In HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced
    • From: ShowSuperHidden="0"
      To: ShowSuperHidden="1"

Step 7

Search and delete AUTORUN.INF files created by WORM_BUZUS.HY that contain these strings

[ Learn More ]

[autorun]
645FF040-5081-101B-9F08-00AA002F954E
S-1-5-21-1644491937-1844823847-682003330-1003

USEAUTOPLAY=1
open=RECYCLER\S-1-5-21-1644491937-1844823847-682003330-1003\autorunme.scr
S-1-5-21-1644491937-1844823847-682003330-1003
S-1-5-21-1644491937-1844823847-682003330-1003

action=Open folder to view files
S-1-5-21-1644491937-1844823847-682003330-1003

shell\open=Open
shell\open\command=RECYCLER\S-1-5-21-1644491937-1844823847-682003330-1003\autorunme.scr
shell\open\default=1
S-1-5-21-1644491937-1844823847-682003330-1003
S-1-5-21-1644491937-1844823847-682003330-1003

Step 8

Scan your computer with your Trend Micro product to delete files detected as WORM_BUZUS.HY. If the detected files have already been cleaned, deleted, or quarantined by your Trend Micro product, no further step is required. You may opt to simply delete the quarantined files. Please check this Knowledge Base page for more information.


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